Automated fluid dispensing system

ABSTRACT

A system and method for automated dispensing of a fluid. The system and method includes accounting for ambient light proximate a dispensing location and generating a reference voltage in response to the ambient light. A second voltage is generating in response to a reflected signal from the location. Dispensing occurs if the difference between the reference voltage and the second voltage is greater than a predetermined amount.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims priority on U.S. ProvisionalApplication No. 61/549,151 filed on Oct. 19, 2011, the contents of whichare fully incorporated herein by reference.

BACKGROUND OF THE INVENTION

Automated battery operated liquid soap dispensing systems typicallyinclude a dispensing spout having a dispensing opening for dispensingliquid soap or foam (collectively or individually “liquid soap”), whichis stored in a reservoir remote from the spout. The liquid soap ispumped to the spout using a pump. Infrared sensing technology using aninfrared sensor is typically used to sense a user's hand beneath thedispensing opening of the spout for activating the pump for pumping theliquid soap. Infrared sensors are sensitive to ambient light and inaddition require relatively high current to operate. The highsensitivity infrared sensor generates a single pulse via a high poweredsource such as high output Infra-Red Diode. If a user's hand is beneaththe spout, the pulse generated by the source is reflected back by theuser's hand to a photo detector. Depending on the strength of thereflected pulse, a microprocessor determines if a hand (or other object)is beneath the spout, and if so, activates the pump for pumping theliquid soap. In some cases, multiple pulses are generated and aplurality of reflected pulses are detected for error determination. Ifthe number of deflected pulses is not within a specified number, thesystem assumes that a sensing error has occurred. The problem with thecurrent systems is that they are not very robust. The strength of thesignals that are reflected at times change due to the ambient lightand/or the reflecting surfaces surrounding the spout. Thus, it may takemore than a few hand swipes beneath the tip of the dispenser spout inorder to activate the pump. At other times, the pump may be activatedwithout a hand moving below the tip as for example when there is achange in the ambient light. A typical IR application uses 50 milliampscurrent and 10 milliseconds duration time for an IR pulse consumingapproximately 500 microamp-hours (μAh). Thus, a more robust power savingand detecting system is desired for battery operated devices.

SUMMARY OF THE INVENTION

In an exemplary embodiment a fluid dispenser is provided. The dispenserincludes a dispensing outlet, a fiber optic cable extending to alocation proximate the dispensing outlet, a light source for generatinga light pulse, the light pulse traveling through the fiber optic cableto the location, a sensor for sensing light received via the fiber opticcable, a microcontroller coupled to the light source and for generatinga voltage in response to the light sensed by the sensor, a comparatorfor comparing voltages generated by the microcontroller and sending asignal to the microcontroller, and a pump for pumping a fluid to thedispenser outlet in response to a signal received from themicrocontroller. In another exemplary embodiment, the fiber optic cableis a single core plastic fiber optic cable. In yet another exemplaryembodiment, the light source is an infrared LED. In a further exemplaryembodiment, the light pulse has a power in the range of 500 to 1000milliamps. In yet a further exemplary embodiment, the light pulse has aduration of one microsecond or less. In another exemplary embodiment,the fiber optic cable includes at least one end which is not polished.In a further exemplary embodiment, the dispenser also includes asplitter coupled to the fiber optic cable, the sensor and the lightsource.

In another exemplary embodiment a fluid dispenser is provided. Thedispenser includes a dispensing outlet, a first fiber optic cableextending to a location proximate the dispensing outlet, a second fiberoptic cable extending to a location proximate the dispensing outlet, alight source for generating a light pulse, the light pulse travelingthrough the first fiber optic cable to the location, a sensor forsensing light received via the second fiber optic cable, amicrocontroller coupled to the light source and for generating a voltagein response to the light sensed by the sensor, a comparator forcomparing voltages generated by the microcontroller and sending a signalto the microcontroller, and a pump for pumping a fluid to the dispenseroutlet in response to a signal received from the microcontroller. In yetanother exemplary embodiment, at least one of the first and second fiberoptic cables is a single core plastic fiber optic cable. In a furtherexemplary embodiment, the light source is an infrared LED. In yet afurther exemplary embodiment, the light pulse has a power in the rangeof 500 to 1000 milliamps. In another exemplary embodiment, the lightpulse has a duration of one microsecond or less. In yet anotherexemplary embodiment, at least one of the first and second fiber opticcables includes at least one end which is not polished.

In a further exemplary embodiment a method for automated dispensing of afluid including is provided. The method includes sensing ambient lightat a location proximate an area in which the fluid will be dispensed,generating a reference voltage in response to the sensed ambient light;sending a signal to the area, sensing a reflection of the signal,generating a second voltage in response to the reflection of the signal,and dispensing the fluid if a difference between the second andreference voltages is greater than a predetermined value. In anotherexemplary embodiment, sensing ambient light is sensing ambient lightthat travels through a fiber optic cable. In yet another exemplaryembodiment, the fiber optic cable is a single core plastic fiber opticcable. In one exemplary embodiment, the fiber optic cable includes atleast one end which is not polished. In another exemplary embodiment,sending a signal includes sending the signal though a fiber optic cable.In yet another exemplary embodiment, sending a signal includes sendingand infrared (IR) pulse. In a further exemplary embodiment, generating areference voltage includes generating a reference voltage with amicrocontroller and communicating such reference voltage to anoperational amplifier. In yet a further exemplary embodiment, generatinga second voltage includes generating the second voltage with amicrocontroller and communicating the second voltage to the operationalamplifier. In another exemplary embodiment, the method further includesdetermining the difference between the second and reference voltages atthe operational amplifier, generating a signal in response to thedifference and communicating the signal to the microcontroller. In yetanother exemplary embodiment, dispensing the fluid includes sending asignal from the microprocessor to a driver and sending a signal from thedriver to a pumping mechanism for pumping the fluid. In a furtherexemplary embodiment, sending a signal to the area comprises sending alight pulse having a power in the range of 500 to 1000 milliamps. In yeta further exemplary embodiment, sending a signal to the area comprisessending a light pulse having a duration of one microsecond or less. Inanother exemplary embodiment, sensing ambient light comprises sensingambient light at time intervals of 0.6 seconds or less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically depicts an exemplary embodiment fluid dispensingsystem of the present invention.

FIG. 2 schematically depicts another exemplary embodiment fluiddispensing system of the present invention.

FIG. 3 depicts a flow chart of an exemplary embodiment method of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

In an exemplary embodiment, a robust and reliable reflective opticaldetection system that uses unpolished plastic fiber optics for guidingan IR signal from a remote sensor location is provided. For example, theinventive system may utilize a plastic fiber optic cable whose ends arenot polished. An exemplary embodiment system has extremely low powerconsumption of 1 μAh that uses about 500 times less energy then commonIR detection systems while maintaining reliable detection at increaseddetection distances. Such exemplary embodiment system is ideal forbattery operated devices. The exemplary embodiment system may useinexpensive unpolished fiber optic cable(s) and a remote sensor locatedon a main printed circuit board (PCB) which is insulated from wetenvironments to prevent damage to sensitive electronics. Low cost ofcomponents and assemblies makes it ideal for high volume consumerproducts. The exemplary system provides for detection and reliableoperation at wide environmental condition from complete darkness to fullsun light, including wet conditions when fully submerged in water.

In an exemplary embodiment, the invention includes a single-core plasticfiber optic cable 10 that leads from a dispenser spout 12, preferablyproximate the tip of the spout, to a splitter 14. In an exemplaryembodiment, the fiber optic is unpolished and more specifically the endsof the fiber optic are unpolished. An exemplary splitter is an opticalsplitter such as mirror or prism or may even be formed by a opticalcoating. Such coatings are well known in the art. The splitter allows asingle cable to be used for both sending a signal and receiving asignal. On an input side 15 of the splitter is attached to a signalsource 16, preferably a light source such as an Infra-Red (IR) Sourcewhich may be an IR LED. The IR Source in an exemplary embodiment iscoupled to a capacitor 18 and to a microcontroller or a microprocessor(collectively or individually referred to herein as “microcontroller” or“MCU”) 20 and which is coupled to an operational amplifier, such as acomparator/amplifier 22 (“OpAmp”). An outlet side 24 of the splitter 14is coupled to a sensor 26, such as an infrared sensor. An exemplarysensor is an IR Diode or an IR Photo Transistor. The sensor is alsocoupled to the OpAmp 22. The OpAmp is connected to the MCU 20. The MCUis also connected to a driver 28 which is connected to a pumping system29, for pumping a fluid such as liquid soap from a reservoir 30 to thedispensing spout outlet 32. A low voltage source 33 (as for example a 6volt source) is connected to the IR Source 16 and the capacitor 18through a current limiter 35. In an exemplary embodiment, the currentlimiter limits the current to the capacitor or the IR Source to 50milliamps. All or some of the components described herein may be formedor attached to a PCB. In addition, although certain components may havebeen described as discrete separate components, in some embodimentsmultiple components may be integrated into a single component.

In operation, the sensor 26 is set to sense ambient light surroundingthe spout tip 12 received through the end 36 of the fiber optic cable 10located at the spout at the predetermined time intervals and communicatesuch sensing by sending a corresponding signal, such as a voltagesignal, to the OpAmp 22. An exemplary predetermined time interval is 0.6second. The signal is a function of the amount of ambient light sensed.In response, the OpAmp 22 amplifies the signal, if and as necessary, andcommunicates it to the MCU 20 which generates a reference signal, orreference voltage (the “reference voltage”), in response to the signalwhich is communicated back to the OpAmp 22. An exemplary intervalbetween the ambient light detection and the generation of the signal(e.g. the time it takes for the generation of the signal) is in anexemplary embodiment 1 to 5 milliseconds depending on the strength ofthe ambient light. This time interval decreases as the strength of theambient light increases. Moreover, at daylight or when the lights are onin a room where the dispenser is located, the reference voltagegenerated may be higher than when it is dark or when the lights are off.A few milliseconds after detecting the ambient light, as for examplewithin 1 to 5 milliseconds, the capacitor 18 discharges and causes theIR Source 16 to generate in an exemplary embodiment, a single high powerlight pulse of 500 to 1000 milliamps having a duration of less than twomicroseconds. In a preferred exemplary embodiment, the IR Source 16generates a single high power pulse of 500 to 1000 milliamps having aduration of one microsecond or less. In an exemplary embodiment, the MCUcauses the capacitor 18 to discharge upon generation of the referencevoltage. The IR light pulse travels from the input side 15 of thesplitter 14 through the fiber optic cable 10 and through the tip end 36of the fiber optic cable. If a reflecting object such as a person's handis proximate the spout in the field of detection of the fiber opticcable tip end 36, at least a portion of the light pulse would bereflected back from such reflecting object through the fiber opticthrough the splitter 14 and to the sensor 26. The strength of thereflected light pulse will be detected by the sensor 26 and communicatedto the OpAmp. The OpAmp will amplify the detected light pulse, if and asnecessary, and communicate it to the MCU. In response the MCU willgenerate a signal, such as a voltage signal (the “reflected voltage”),and send it back to the OpAmp 22. The generated voltage signal by theMCU is a function of the sensed reflected pulse strength. The OpAmpwould compare the reference voltage and the reflected voltage and inresponse generate a TTL (transistor-transistor logic) signal which isthen communicated to the MCU 20. If the difference between the referencevoltage and the reflected voltage is greater than a predeterminedamount, the OpAmp send a first signal to the MCU. If the difference involtage between the reference voltage and the reflected voltage is notgreater than the predetermined amount, then the OpAmp sends a secondsignal or not signal to the MCU. If the MCU receives the signal, it thensend a signal to the driver 28 to operate the pumping system 29 forpumping the liquid soap (or other fluid) from the reservoir 30 to thedispenser outlet 32. The MCU does not provide a signal to the driver foroperating the pumping system when it receives no signal or when itreceives the second signal from the OpAmp.

If a user's hand is not in the field of detection of the fiber opticcable to reflect the single pulse, there will not be any reflectedsignal and the strength of any signal received by the sensor 26 would bethat of the ambient light. Consequently, the reflected voltage generatedwould be same or very close to the initially measured reference voltage.Thus, the difference in the two voltages will be less than thepredetermined amount and the OpAmp will generate no signal or the secondsignal and the MCU would not send a signal to driver 28 to operate thepumping system 29. The process is then repeated as the sensor 26 sensesambient light again within the predetermined time interval.

After the single pulse voltage is sent, the capacitor is recharged fromthe low voltage source 33 so that it would be ready to send anothersignal after another ambient light detection has been made by thesensor.

In another exemplary embodiment as shown in FIG. 2, instead of anoptical splitter and a single fiber optic cable, two single core fiberoptic plastic cables 10 a, 10 b may be used. A first fiber optic plasticcable 10 a is used for sending a signal and a second fiber optic plasticcable 10 b is used for receiving a signal. The IR Source 16 is coupledto the first fiber optic cable 10 a through which a signal is sent,while the sensor 26 is coupled to the second fiber optic cable 10 bthrough which a signals is received.

In summary as shown in FIG. 3, the level of ambient light at a locationproximate or at a dispensing end of a dispenser is detected atpredetermined time intervals (100). A reference voltage is generated inresponse to the sensed ambient light (102). A signal such as an IRsignal is sent to the location proximate or at the dispensing end of thedispenser (104). A level of a signal (e.g., light or a reflection of theIR signal) emanating at the location within the predetermined timeinterval is detected (106), a second voltage in response to the detectedsignal or ambient light (108). If the difference between the referencevoltage and the second voltage is greater than a predetermined amount(110), then fluid is dispensed from the dispenser (112). The process isthen repeated.

As can be seen with the present invention, a lower cost robustactivating system is provided. The system has low power consumption, asit does not need a high powered source for generating pulses as theprior art system. It also does not require high quality polished glasssingle-core or multi-core fiber optic cable. In fact, the present systemworks with plastic fiber optic cables that are not polished. Applicanthas also discovered that the system can operate robustly even whensubmerged in water. Furthermore, by accounting for the ambient lightpresent, the system significantly reduces, if not alleviates, all thefalse activations or the mis-activations associated with prior artdispenser activating systems, which do not account for the ambientlight. For example, with the prior art systems, if the ambient light issignificant, the reflection may be diluted, and thus, the system may notdetermine that a user is intending to activate the pumping system.

Although the present invention has been described and illustrated inrespect to exemplary embodiments, it is to be understood that it is notto be so limited, since changes and modifications may be made thereinwhich are within the full intended scope of this invention ashereinafter claimed. For example, the invention may be practiced inanother exemplary embodiment without using a capacitor 18 or with usingplastic or glass fiber optic cables whose ends may or may not bepolished.

What is claimed is:
 1. A fluid dispenser comprising: a dispensingoutlet; a fiber optic cable extending to a location proximate thedispensing outlet; a light source for generating a light pulse, saidlight pulse traveling from said light source through the fiber opticcable to said location; a sensor for sensing light received via thefiber optic cable from said location, said light comprising at least oneof ambient light and a reflection of said light pulse; a comparator forreceiving a signal from said sensor corresponding to said sensed light,for amplifying said signal, for determining if there is a reflection ofsaid light pulse in said sensed light or if said sensed light is ambientlight, and for generating a transistor-transistor logic (TTL) signal ifthe reflection of said light pulse is determined; a microcontrollerseparate from said comparator for receiving the TTL signal from saidcomparator; a capacitor coupled to the light source, wherein dischargingof said capacitor causes the generation of said light pulse, saidcapacitor discharging in 5 milliseconds or less after said comparatordetermines that the sensed light is ambient light; and a pump forpumping a fluid to the dispenser outlet in response to a signal receivedfrom said microcontroller in response to said TTL signal.
 2. Thedispenser of claim 1, wherein the fiber optic cable is a single coreplastic fiber optic cable.
 3. The dispenser of claim 1, wherein thelight source is an infrared LED.
 4. The dispenser of claim 1, whereinsaid light pulse has a power in the range of 500 to 1000 milliamps. 5.The dispenser of claim 4, wherein the light pulse has a duration of onemicrosecond or less.
 6. The dispenser of claim 1, wherein the lightpulse has a duration of one microsecond or less.
 7. The dispenser ofclaim 1, wherein the fiber optic cable comprises at least one end whichis not polished.
 8. The dispenser of claim 1, further comprising asplitter coupled to the fiber optic cable, the sensor and the lightsource.
 9. A fluid dispenser comprising: a dispensing outlet; a firstfiber optic cable extending to a first location proximate the dispensingoutlet; a second fiber optic cable extending to a second locationproximate the dispensing outlet; a light source for generating a lightpulse, said light pulse traveling from said light source through thefirst fiber optic cable to said first location; a sensor for sensinglight received via the second fiber optic cable from said secondlocation, said light comprising at least one of ambient light and areflection of said light pulse; a comparator for receiving a signal fromsaid sensor corresponding to said sensed light, for amplifying saidsignal, for determining if there is a reflection of said light pulse insaid sensed light or if said sensed light is ambient light, and forgenerating a transistor-transistor logic (TTL) signal if the reflectionof said light pulse is determined; a microcontroller separate from saidcomparator for receiving the TTL signal from said comparator; acapacitor coupled to the light source, wherein discharging of saidcapacitor causes the generation of said light pulse, said capacitordischarging in 5 milliseconds or less after said comparator determinesthat the sensed light is ambient light; and a pump for pumping a fluidto the dispenser outlet in response to a signal received from saidmicrocontroller in response to said TTL signal.
 10. The dispenser ofclaim 9, wherein at least one of the first and second fiber optic cablesis a single core plastic fiber optic cable.
 11. The dispenser of claim9, wherein the light source is an infrared LED.
 12. The dispenser ofclaim 9, wherein said light pulse has a power in the range of 500 to1000 milliamps.
 13. The dispenser of claim 12, wherein the light pulsehas a duration of one microsecond or less.
 14. The dispenser of claim 9,wherein the light pulse has a duration of one microsecond or less. 15.The dispenser of claim 9, wherein at least one of the first and secondfiber optic cables comprises at least one end which is not polished. 16.The dispenser of claim 1 wherein said dispenser has a power ofconsumption of 1 μAh.
 17. The dispenser of claim 1 further comprising a6 volt source coupled to the light source.
 18. The dispenser of claim 9wherein said dispenser has a power of consumption of 1 μAh.
 19. Thedispenser of claim 9 further comprising a 6 volt source coupled to thelight source.
 20. The dispenser of claim 4, wherein the light pulse hasa duration of two microseconds or less.
 21. The dispenser of claim 1,wherein the light pulse has a duration of two microseconds or less. 22.The dispenser of claim 1, wherein the capacitor discharges within 1 to 5milliseconds after said comparator determines that the sensed light isambient light.
 23. The dispenser of claim 12, wherein the light pulsehas a duration of two microseconds or less.
 24. The dispenser of claim9, wherein the light pulse has a duration of two microseconds or less.25. The dispenser of claim 9, wherein the capacitor discharges within 1to 5 milliseconds after said comparator determines that the sensed lightis ambient light.